R.S. Sudheesh and N. Siva Prasad
The purpose of this paper is to study the effect of trailing liquid nitrogen (LN2) heat sink on arc welding of mild steel plates. The effect on temperature field, stress and…
Abstract
Purpose
The purpose of this paper is to study the effect of trailing liquid nitrogen (LN2) heat sink on arc welding of mild steel plates. The effect on temperature field, stress and distortions are studied using experimental and numerical methods.
Design/methodology/approach
The methodology consists of experimental and numerical methods. The temperature measured at a point near the arc is used to estimate the cooling capacity of the heat sink using inverse heat transfer (IHT) method. The estimated cooling flux is applied to the finite element model to study the stress and distortions using LN2 heat sink. The stresses are measured using X‐ray diffraction technique and the distortions using dial gauges.
Findings
IHT method has been employed in estimating the cooling capacity of the LN2 jet. This has been applied to welding to study the effect on weld induced stresses and distortions. The method can be extended to calculate the heat removal rate in various manufacturing processes where cooling is employed.
Research limitations/implications
The lack of temperature dependent material properties resulted in deviation of stresses between analytical results and experiment values.
Originality/value
IHT method developed for heat removal capacity of trailing heat sink is a contribution. The estimated heat flux shows good agreement in analytical and experimental temperature values. These temperatures have been extended to calculate stresses and out of plane distortions in welding and there is a reasonable agreement between finite element analysis and experimental results.
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Baharak Hooshyarfarzin, Mostafa Abbaszadeh and Mehdi Dehghan
The main aim of the current paper is to find a numerical plan for hydraulic fracturing problem with application in extracting natural gases and oil.
Abstract
Purpose
The main aim of the current paper is to find a numerical plan for hydraulic fracturing problem with application in extracting natural gases and oil.
Design/methodology/approach
First, time discretization is accomplished via Crank-Nicolson and semi-implicit techniques. At the second step, a high-order finite element method using quadratic triangular elements is proposed to derive the spatial discretization. The efficiency and time consuming of both obtained schemes will be investigated. In addition to the popular uniform mesh refinement strategy, an adaptive mesh refinement strategy will be employed to reduce computational costs.
Findings
Numerical results show a good agreement between the two schemes as well as the efficiency of the employed techniques to capture acceptable patterns of the model. In central single-crack mode, the experimental results demonstrate that maximal values of displacements in x- and y- directions are 0.1 and 0.08, respectively. They occur around both ends of the line and sides directly next to the line where pressure takes impact. Moreover, the pressure of injected fluid almost gained its initial value, i.e. 3,000 inside and close to the notch. Further, the results for non-central single-crack mode and bifurcated crack mode are depicted. In central single-crack mode and square computational area with a uniform mesh, computational times corresponding to the numerical schemes based on the high order finite element method for spatial discretization and Crank-Nicolson as well as semi-implicit techniques for temporal discretizations are 207.19s and 97.47s, respectively, with 2,048 elements, final time T = 0.2 and time step size τ = 0.01. Also, the simulations effectively illustrate a further decrease in computational time when the method is equipped with an adaptive mesh refinement strategy. The computational cost is reduced to 4.23s when the governed model is solved with the numerical scheme based on the adaptive high order finite element method and semi-implicit technique for spatial and temporal discretizations, respectively. Similarly, in other samples, the reduction of computational cost has been shown.
Originality/value
This is the first time that the high-order finite element method is employed to solve the model investigated in the current paper.
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Ramasubbu Narasimmalu and Ramabalan Sundaresan
AA8090 aluminum alloy is used in industrial applications for weight reduction purposes. However, its usage is limited due to shortcomings such as low wear resistance. Hence, the…
Abstract
Purpose
AA8090 aluminum alloy is used in industrial applications for weight reduction purposes. However, its usage is limited due to shortcomings such as low wear resistance. Hence, the purpose of this study is to improve the wear properties of the material. A particle strengthening mechanism was tried to improve the wear properties of materials.
Design/methodology/approach
AA8090 aluminum alloy composites were prepared by stir casting methods using AA8090, boron carbide (B4C) and aluminum oxide (Al2O3) materials. Totally, four different types of composites were prepared, namely, AA/3Al, AA/1BC-2Al, AA/2BC-1Al and AA/3BC. Wear behavior and mechanical properties of the composites were analyzed by conducting wear test, microhardness test, tensile test and morphological analysis.
Findings
Results showed that the composite materials showed superior properties compared with AA8090 alloy due to the reinforcing effect of B4C and Al2O3 particles. Further, the AA/3BC composite showed 12.9% and 10.8% enhancement in microhardness and tensile strength, respectively. Further, a minimum wear rate of 0.009 × 10–3 mm3/m was observed for AA/3BC composite.
Originality/value
This study is original and would add new information to the literature. Further, it solves the problem of low wear resistance issues in AA8090 aluminum alloy materials.
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Reza Masoumzadeh, Mostafa Abbaszadeh and Mehdi Dehghan
The purpose of this study is to develop a new numerical algorithm to simulate the phase-field model.
Abstract
Purpose
The purpose of this study is to develop a new numerical algorithm to simulate the phase-field model.
Design/methodology/approach
First, the derivative of the temporal direction is discretized by a second-order linearized finite difference scheme where it conserves the energy stability of the mathematical model. Then, the isogeometric collocation (IGC) method is used to approximate the derivative of spacial direction. The IGC procedure can be applied on irregular physical domains. The IGC method is constructed based upon the nonuniform rational B-splines (NURBS). Each curve and surface can be approximated by the NURBS. Also, a map will be defined to project the physical domain to a simple computational domain. In this procedure, the partial derivatives will be transformed to the new domain by the Jacobian and Hessian matrices. According to the mentioned procedure, the first- and second-order differential matrices are built. Furthermore, the pseudo-spectral algorithm is used to derive the first- and second-order nodal differential matrices. In the end, the Greville Abscissae points are used to the collocation method.
Findings
In the numerical experiments, the efficiency and accuracy of the proposed method are assessed through two examples, demonstrating its performance on both rectangular and nonrectangular domains.
Originality/value
This research work introduces the IGC method as a simulation technique for the phase-field crystal model.
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Sharifatul Ain Binti Sharifuddin, Salwani Binti Ismail, Imran Abdullah, Irfan Mohamad and Javeed Shaikh Mohammed
Staphylococcus aureus (S. aureus), Klebsiella pneumoniae (K. pneumoniae) and Streptococcus pneumoniae (S. pneumoniae) are among the pathogens detected during Hajj pilgrimage known…
Abstract
Purpose
Staphylococcus aureus (S. aureus), Klebsiella pneumoniae (K. pneumoniae) and Streptococcus pneumoniae (S. pneumoniae) are among the pathogens detected during Hajj pilgrimage known to cause pneumonia. This study aims to evaluate the antibacterial activity of activated carbon cloth (ACC) with Ag+ impregnated with zinc oxide nanoparticles (ZnO NPs) against these pathogens.
Design/methodology/approach
ZnO NPs were impregnated into ACC-Ag+ via layer-by-layer (LbL) self-assembly. Scanning electron microscope (SEM) was used to observe the fine surface morphological details of the ACC-Ag+-ZnO sheets. Antibacterial activity of the ACC-Ag+-ZnO sheets was evaluated using the disk-diffusion susceptibility assay. Allergy patch test was done to evaluate allergic reactions of the ACC-Ag+-ZnO sheets on human skin.
Findings
SEM micrographs showed successful impregnation of ZnO NPs into the ACC-Ag+ sheets. Disk-diffusion susceptibility assay results of ACC-Ag+-ZnO sheets against S. aureus, K. pneumoniae and S. pneumoniae showed good antibacterial activity; with 1.82 ± 0.13 mm zone of inhibition for S. pneumoniae, at a ZnO concentration of 0.78 mg mL-1. No signs of human skin irritation were observed throughout the allergy patch test.
Originality/value
Results indicate that ACC-Ag+-ZnO sheets could potentially be embedded within surgical face masks (pilgrims’ preferred) to reduce the risks involved with the transmission of respiratory tract infections during and after mass gatherings (e.g. Hajj/Umrah, Olympics).
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Xu Wang, Chunyan Dai and Linhao Bao
The purpose of this paper is to conduct a thorough study of the current research status and trends of Artificial Intelligence-Generated Content (AIGC), which is thriving and…
Abstract
Purpose
The purpose of this paper is to conduct a thorough study of the current research status and trends of Artificial Intelligence-Generated Content (AIGC), which is thriving and exerting significant influences on society, the economy and technology. This study will encompass both the ample opportunities and the array of emerging risks and challenges associated with AIGC. Furthermore, this paper seeks to propose practical optimization strategies to facilitate its continued development.
Design/methodology/approach
A total of 12,702 documents in Scopus, CNKI and Altmetric.com databases are analyzed in this paper. The visualization tools of CiteSpace and Netdraw are used to systematically analyze AIGC from macro, meso and micro perspectives based on bibliometric indicators. The analysis is combined with altmetrics indicators to identify hotspots in AIGC-related research and predict future development trends. Finally, substantive optimization suggestions for the development of AIGC are put forward.
Findings
Research has found that firstly, both domestic and international research in the field of AIGC is actively catching up with the pace of the era. Institutions and authors recognize the indispensability of collaboration, leading to the emergence of interdisciplinary cooperation trends. Secondly, at the thematic research level, both domestic and international studies cover the overall trends of AIGC, including technology, applications, challenges and coping strategies. However, international scholars tend to focus more on technological breakthroughs, while domestic researchers emphasize the formulation of national laws and regulations. Finally, through the analysis of hotspots and trends, it is predicted that future research will focus more on addressing the legal issues regarding the originality of AIGC, enhancing its interactivity, optimizing its applications, emphasizing ethical considerations and efficiently addressing major social issues such as pandemics using AIGC technology. Corresponding optimization strategies are proposed to ensure the development of AIGC is consistent with global consensus and values, creating a beneficial environment for its sustainable development.
Originality/value
Firstly, this paper integrates data from three databases and uses multiple software tools to conduct a comparative analysis of the research trends in AIGC from both domestic and international perspectives. Secondly, this paper not only analyzes the academic influence of AIGC-related research through bibliometric indicators but also combines altmetrics indicators to explore the public’s attitude toward AIGC. This method systematically reveals the overall development trends, leading institutions and researchers, thematic research areas, hotspot evolution and future development trends of AIGC-related research, providing theoretical references for subsequent scholars in AIGC research. Additionally, this paper helps governments, institutions and organizations to precisely and wisely formulate policies and investments, as well as to effectively comprehend the development trends of AIGC and promote the advancement of AIGC technology and applications.
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An Nee Lau, Mohd Hafiz Jamaludin and Jan Mei Soon
The purpose of this paper is to determine the understanding of halal concept among food production workers and to develop a generic Halal Control Point (HCP) Plan for the…
Abstract
Purpose
The purpose of this paper is to determine the understanding of halal concept among food production workers and to develop a generic Halal Control Point (HCP) Plan for the manufacturing of processed foods.
Design/methodology/approach
A mixed-method (interviews, surveys and microbiological analyses) approach was used to analyze the hygiene and halal practices of four food processing plants in Penang, Malaysia. In total, 200 food production workers were surveyed (and quality assurance staff were interviewed) to determine their understanding of halal concepts and attitude towards halal food products. Adenosine triphosphate (ATP) swabbing tests were conducted to determine the hygiene of workers and food contact surfaces. End products were sampled and enumerated for total bacterial count.
Findings
The swabbing tests of food contact surfaces (i.e. tabletops) showed that only Company C (oat) and Company D (coffee powder) passed the ATP hygiene test (= 10 reflective light units [RLU]). The results obtained from all workers’ hands and aprons indicated a 100 per cent failure rate (>30 RLU). No ATP was detected on the packaging materials from all companies. The microbiological findings indicated that the end products are satisfactory and were below detection limits as verified by the enumeration done on the food samples. Besides, from the interview sessions conducted with the quality assurance staff, one generic Halal Control Points (HCPs) plan and four specific HCP plan tables were developed for the manufacturing process of halal food products for each company.
Originality/value
The HCP plans will be of value for food industry seeking to identify potential point sources of haram contamination and halal control points for their food production processes.
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Gopinath Selvam, Mohan Kamalanandhini, Muthuvel Velpandian and Sheema Shah
The construction projects are highly subjected to uncertainties, which result in overruns in time and cost. Realistic estimates of workforce and duration are imperative for…
Abstract
Purpose
The construction projects are highly subjected to uncertainties, which result in overruns in time and cost. Realistic estimates of workforce and duration are imperative for construction projects to attain their intended objectives. The aim of this study is to provide accurate labor and duration estimates for the construction projects, considering actual uncertainties.
Design/methodology/approach
The dataset was formulated from the information collected from 186 construction projects through direct interviews, group discussions and questionnaire methods. The actual uncertainties and exposure conditions of construction activities were recorded. The data were verified with the standard guideline to remove the outliers. The prediction model was developed using support vector regression (SVR), a machine learning (ML) method. The performance was evaluated using the widely adopted regression metrics. Further, the cross validation was made with the visualization of residuals and predicted errors, ridge regression with transformed target distribution and a Gaussian Naive Bayes (NB) regressor.
Findings
The prediction models predicted the duration and labor requirements with the consideration of actual uncertainties. The residual plot indicated the appropriate use of SVR to develop the prediction model. The duration (DC) and resource constraint (RC) prediction models obtained 80 and 82% accuracy, respectively. Besides, the developed model obtained better accuracy for the training and test scores than the Gaussian NB regressor. Further, the range of the explained variance score and R2 was from 0.95 to 0.97, indicating better efficiency compared with other prediction models.
Research limitations/implications
The researchers will utilize the research findings to estimate the duration and labor requirements under uncertain conditions and further improve the construction project management practices.
Practical implications
The research findings will enable industry practitioners to accurately estimate the duration and labor requirements, considering historical uncertain conditions. A precise estimation of resources will ensure the attainment of the intended project outcomes.
Social implications
Delays in construction projects will be reduced by implementing the research findings, which significantly ensures the effective utilization of resources and attainment of other economic benefits. The policymakers will develop a guideline to develop a database to collect the uncertainties of the construction projects and relatively estimate the resource requirements.
Originality/value
This is the first study to consider the actual uncertainties of construction projects to develop RC and DC prediction models. The developed prediction models accurately estimate the duration and labor requirements with minimal computational time. The industry practitioners will be able to accurately estimate the duration and labor requirements using the developed models.
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Tirth Patel, Brian H.W. Guo and Yang Zou
This article aims to explore valuable insights into the construction progress monitoring (CPM) research domain, which include main research topics, knowledge gaps and future…
Abstract
Purpose
This article aims to explore valuable insights into the construction progress monitoring (CPM) research domain, which include main research topics, knowledge gaps and future research themes. For a long time, CPM has been significantly researched with increasing enthusiasm. Although a few review studies have been carried out, there is non-existence of a quantitative review study that can deliver a holistic picture of CPM.
Design/methodology/approach
The science mapping-based scientometric analysis was systematically processed with 1,835 CPM-related journal articles retrieved from Scopus. The co-authorship analysis and direct citation analysis were carried out to identify the most influential researchers, countries and publishers of the knowledge domain. The co-occurrence analysis of keyword was assessed to reveal the most dominating research topics and research trend with the visual representation of the considered research domain.
Findings
This study reveals seven clusters of main research topics from the keyword co-occurrence analysis. The evolution of research confirms that CPM-related research studies were mainly focused on fundamental and traditional CPM research topics before 2007. The period between 2007 and 2020 has seen a shift of research efforts towards digitalization and automation. The result suggests Building Information Modelling (BIM) as the most common, growing and influential research topic in the CPM research domain. It has been used in combination with different data acquisition technologies (e.g. photogrammetry, videogrammetry, laser scanning, Internet of Things (IoT) sensors) and data analytics approaches (e.g. machine learning and computer vision).
Practical implications
This study provides the horizon of potential research in the research domain of CPM to researchers, policymakers and practitioners by availing of main research themes, current knowledge gaps and future research directions.
Originality/value
This paper represents the first scientometric study depicting the state-of-the-art of the research by assessing the current knowledge domain of CPM.
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Thi Thuy Hang Pham, Thi Truc Quynh Ho, Be Thi Ngoc Nguyen, Hung Thanh Nguyen and Thi Ha Nguyen
This study aims to investigate the conditional indirect effect of academic self-efficacy in the interplay between academic motivation and academic satisfaction through academic…
Abstract
Purpose
This study aims to investigate the conditional indirect effect of academic self-efficacy in the interplay between academic motivation and academic satisfaction through academic engagement among university students.
Design/methodology/approach
A cross-sectional study was performed on 1,638 Vietnamese university students (31.9% males and 68.1% females) aged 16 to 36 (Mean = 20.06, SD = 1.428). The participants filled out a questionnaire with the Vietnam versions of the General Self-Efficacy Scale, Academic Motivation Scale, Academic Life Satisfaction Scale and Academic Engagement Scale. Model 4 and Model 7 in the PROCESS macro were used for the mediation analysis and the moderated mediation analysis.
Findings
Results showed that the indirect effect of academic engagement on the academic motivation-academic satisfaction link was significant. Furthermore, academic self-efficacy moderated this indirect effect. The indirect effect was stronger among students with high academic self-efficacy and weaker among students with low academic self-efficacy.
Originality/value
This study’s findings contribute to educational research on academic satisfaction and can be used by institutions of higher education and educators to enhance academic satisfaction among university students.